With a margin of slightly more than 11 percent, Sanford voters approved changes to the town’s charter designed to make government more efficient and to encourage economic growth.

A majority of voters in every ward, as well as absentee voters, cast ballots in favor of the new charter recommended by the Charter Commission. The resulting tally was 4,018 votes (55.6 percent) for the new charter and 3,207 votes (44.4 percent) against, according to “unofficial election results” sent by the town clerk’s office to the Sanford News at 5 a.m. on Wednesday.

As a result of the charter’s passage, Sanford will change from a town to a city, will elect a mayor and will eliminate the annual town meeting and put budgets in the hands of all voters.

The changes outlined in the new charter will take effect Jan. 1, 2013. For the first year, the mayor will be elected by the city council from among its members and will serve as interim mayor until the next regular election when a mayor will be elected by voters. The first elected mayor will serve a three-year term. After his or her term expires on Dec. 31, 2016, the term of office will be two years. No one may serve as mayor for more than three consecutive two-year terms.

The position of mayor will be equivalent to that of the current chair of the town council, except that voters will choose the mayor directly with their votes. The mayor will be recognized as head of the city government for all ceremonial purposes, but will not have regular administrative or executive duties (except as outlined in the charter). The mayor will preside at city council meetings, will be considered as a seventh member of the city council, and will vote as a member of the city council.

The city manager — currently the town manager — will continue to be the chief executive officer and the head of the administrative branch of the city government.

Sanford’s representative town meeting will be eliminated and voters will vote on the municipal budget and the school budget each year, as they currently do with the school budget.

The new charter also replaces the current 11-member finance committee with a seven-member budget committee. Members will be appointed to one-year terms by the city council and will include four members at large and three members from the city council.

The charter also requires that two percent of Sanford’s capital improvement program be designated specifically to infrastructure and that reserves set aside for capital improvements be increased from the current two percent of the previous year’s city and school budgets (combined) to four percent over the next four years. The change will provide more funding for road maintenance and repairs as well as other long-term needs.